相关论文: The cluster abundance in cosmic string models for …

We discuss the generation and evolution of density perturbations during the large curvature phase of string cosmology. We find that perturbations in the scalar components of the metric evolve with cosmic time as $\exp (\gamma H_st)$ where…

We propose a new method to probe for variations in the fine structure constant alpha using clusters of galaxies, opening up a window on a new redshift range for such constraints. Hot clusters shine in the X-ray mainly due to bremsstrahlung,…

We use the POTENT reconstruction of the mass density field in the nearby universe to estimate the amplitude of the density fluctuation power spectrum for various cosmological models. We find sigma_8\Omega_m^{0.6}= 1.3^{+0.4}_{-0.3}, almost…

We present an analysis of cosmological models with mixed dark matter (spectrum slope of density perturbations $n_S \in [0.6, 1.6]$, hot dark matter abundance $\Omega_\nu \in [0.0, 0.6]$) in spatially flat Universe, based on Press-Schechter…

We present constraints on cosmic structure growth from the analysis of galaxy clustering and galaxy-galaxy lensing with galaxies from the Dark Energy Spectroscopic Instrument (DESI) Data Release 1. We analyze four samples drawn from the…

We show how two simple modifications to the standard cosmic string scenario for structure formation compare to the recently released Boomerang data set. Namely we consider pure string closed models and mixed models where both inflation and…

We discuss the problem of estimating the characteristic length scale $\xi_{\rm s}$, and hence the initial density, of a system of cosmic strings formed at a continuous, second-order phase transition in the early universe. In particular, we…

In this paper a relative number density parameter, called the neighborhood function, is introduced so that the crowded nature of the neighborhood of individual sources can be described. With this parameter one can determine the probability…

We constrain the cosmological density of cosmic string loops using two observational signatures -- gravitational microlensing and the Kaiser-Stebbins effect. Photometry from RXTE and CoRoT space missions and pulsar timing from Parkes Pulsar…

The influence of higher-order terms in the K\"{a}hler potential of the supergravity D-term inflation model on the density perturbation is studied. We show that these terms can make the inflaton potential flatter, which lowers the energy…

The measurements of cluster abundances, gravitational lensings, redshift space distortions and peculiar velocities at lower redshifts point out to much smaller sigma_8 than its value deduced from the measurements of the CMB fluctuations…

We demonstrate that string motivated inflation ending via tachyonic instability leaves a detectable imprint on the cosmic microwave background (CMB) radiation by virtue of the excitation of non-Gaussian gravitational fluctuations. The…

We present the results of analysis of constraints on cosmological parameters from cosmic microwave background (CMB) alone and in combination with galaxy cluster baryon fraction assuming inflation--generated adiabatic scalar fluctuations.…

Cluster abundance measurements are among the most sensitive probes of the amplitude of matter fluctuations in the universe, which in turn can help constrain other cosmological parameters, like the dark energy equation of state or neutrino…

We study the angular clustering of Quaia, a Gaia- and unWISE-based catalog of over a million quasars with an exceptionally well-defined selection function. With it, we derive cosmology constraints from the amplitude and growth of structure…

Likelihood fitting to two-point clustering statistics made from galaxy surveys usually assumes a multivariate normal distribution for the measurements, with justification based on the central limit theorem given the large number of…

A recent observation of Steidel et al. indicates that a substantial fraction of giant galaxies were formed at an epoch as early as redshift $z>3-3.5$. We show that this early formation of giant galaxies gives strong constraints on models of…

We revisit the possibility that an excess in the CMB power spectrum at small angular scales (CBI, ACBAR) can be due to galaxy clusters (or compact sources in general). We perform a Gaussian analysis of ACBAR-like simulated data based on…

The abundance of local clusters is a traditional way to derive the amplitude of matter fluctuations. In the present work, by assuming that the observed baryon content of clusters is representative of the universe, we show that the mass…

We propose an alternative scenario to cosmic inflation for producing the initial seeds of cosmic structures. The cosmological fluctuations are generated by thermal fluctuation of the energy density of the ideal string gas in three compact…